#include<iostream>
#include<stack>
#include<cassert>


int main()
{
	std::stack<int> a,b;

	a.push(5);
	b = a;
	int s1 = a.top()=1;
	int s2 = b.top();
//	a.pop();
	int s = a.top();
	return 0;
}

